Conventionally, rotary electric machines are known in which a space is provided between a inner cylinder that supports a stator core and an outer cylinder that further encloses the inner cylinder, and in which cooling of the stator core is performed by allowing cooling water to flow through the space (see PTL 1, for example).
In this case, both end portions of the inner cylinder and the outer cylinder are sealed around the entire circumference using O-rings in order to ensure airtightness in the cooling passage (see PTL 1, for example).